1. Field of Invention
The present invention relates to an alternating current contactor (AC contactor) having a protective function, and more particularly to an AC contactor with an electronic short circuit self-locking function.
2. Description of Related Arts
It is well known that AC contactors are widely adopted in currently existing control equipments for switching on/off or controlling of power lines. Usually a main contact is adopted to open or close a circuit, an auxiliary contact is adopted to execute a control instruction. The main contact is ordinarily a normally open contact. The auxiliary contacts ordinarily comprise a pair of normally open contacts and a pair of normally closed contacts. Cooperated with a main circuit, a small-scale contactor is often adopted as an intermediate relay.
The contacts of the AC contactors are made of silver alloy, and have good conductivity and high-temperature ablation resistance.
In this application, a structure that is capable of achieve basic functions of an AC contactor in conventional techniques is called an AC contactor body.
In actual processes, the AC contactor mentioned above is capable of breaking a circuit under instructions of a control equipment while working. If a thermal relay is not capable of operating a protection action timely when short circuit occurs, a contactor is not capable of breaking timely, or if an electronic protective equipment does not have a self-locking protection function in a short circuit fault, the AC contactor body usually executes instructions of the control equipment to attach up, which leads to damage of equipments or a fire disaster. In addition, a short circuit accident occurs on the AC contactor body, and circuit breaking action is generated. Technicians of the related arts only see the result of the circuit breaking, but are not capable of knowing causes of the circuit breaking, which confuses maintenance staffs as well.
In view of the defects mentioned above, inventors finally obtained the present invention after a long period of research and practice.